Here in the UK, there is exactly one layer: the NHS. It negotiates prices directly with drug suppliers, and as the sole buyer (monopsony) is able to get a great deal. It also sets the prices paid by consumers (the prescription price), which is a flat price charged for all drugs (yes really all of them) and is currently £9.15 (about 11 USD) for a prescription (i.e. a full course of multiple tablets of the drug). If you are given drugs in a hospital as part of an inpatient treatment the charge is usually nil.